As medical device technologies continue to evolve, neurostimulator devices have gained much popularity in the medical field. Neurostimulator devices are typically battery-powered devices that are designed to deliver electrical stimulation to a patient. Through proper electrical stimulation, the neurostimulator devices can provide pain relief for patients. In effect, the electrical signals sent by the neurostimulator devices “mask” or modify the pain signals before the pain signals reach the patient's brain. As a result, the patient may feel only a tingling sensation (known as “Paresthesia) in the area that is stimulated instead of pain. For example, peripheral nerve stimulation has been used to treat chronic pain emanating from a patient's extremity, such as in the patient's arm and/or leg. A typical peripheral neurostimulator (PNS) device may include one or more integrated circuit chips containing the control circuitry and neurostimulation circuitry. The PNS device may also include a plurality of electrodes that are in contact with different areas of a patient's body. The PNS device typically includes a battery, either permanent or rechargeable, that is utilized to power the stimulation circuitry and the external communications. Controlled by the control circuitry within the neurostimulator, the electrodes are each capable of delivering electrical stimulation to their respective target contact areas. Thus, the patient can use the PNS device to stimulate areas in a localized manner.
In spite of recent advances, conventional PNS devices still have various shortcomings. As an example, the nerves in a spinal cord are typically arranged more orderly and run along a linear path, whereas the nerves to be stimulated in peripheral nerve stimulation usually wind tortuously along a neurovascular bundle. Therefore, a typical paddle lead for a conventional PNS device or for spinal cord stimulation does not offer the flexibility and versatility needed to stimulate the target nerve fibers for peripheral nerve stimulation, as they are not configured to allow electrical stimulation energy to follow the tortuous peripheral nerve targets selectively. As another example, conventional PNS devices typically require an antenna to receive telemetry signals and a separate charging coil to receive charging signals. As a result, PNS design is more complex and more expensive. As yet another example, conventional PNS devices typically do not employ sophisticated power maximization techniques to reduce power consumption. Consequently, conventional PNS devices tend to have battery life that does not last as long as desired. The short battery life may lead to user dissatisfaction. As yet another example, it may be difficult to determine a target nerve site for applying stimulation.
As a result, although existing systems and methods of peripheral neurostimulation have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.